(Co)polymers of vinyl monomers (for example, copolymers of isooctyl acrylate or other high boiling acrylates with acrylic acid or acrylamide) often contain residual monomer in the final polymerized product. Residual monomer in the final polymerized product is undesirable, however, because it can give off unpleasant odors, or potentially be toxic or corrosive.
Although polymerizations can be carried to extremes where conversions of monomer starting materials (“primary monomer”) to copolymer are above 95%, it is almost impossible to eliminate all unreacted primary monomer during the initial reaction. In addition, unreacted primary monomers are not easily removed by volatilization because of their low volatility.
Scavenger monomers are sometimes added to copolymerize with residual primary monomer when polymerization of the primary monomers is substantially complete (that is, at least about 80% complete) in order to lower the level of residual primary monomer (see, for example, U.S. Pat. No. 4,737,577).